1. Field of the Invention
The present invention relates generally to energy efficient Ethernet networks and, more particularly, to energy efficient Ethernet with a low power active idle transmission mode.
2. Introduction
Energy costs continue to escalate in a trend that has accelerated in recent years. Such being the case, various industries have become increasingly sensitive to the impact of those rising costs. One area that has drawn increasing scrutiny is the IT infrastructure. Many companies are now looking at their IT systems' power usage to determine whether the energy costs can be reduced. For this reason, an industry focus on energy efficient networks has arisen to address the rising costs of IT equipment usage as a whole (i.e., PCs, displays, printers, servers, network equipment, etc.).
In designing an energy efficient solution, one of the considerations is the utilization of the network link. For example, many network links are typically in an idle state between sporadic bursts of data. During this idle state, idle signals are transmitted. Unfortunately, the transmission of idle signals wastes energy and adds to the radiated emission levels.
While identification of low link utilization periods can provide opportunities to produce energy savings, many traffic profiles can include regular or intermittent low-bandwidth traffic, with bursts of high-bandwidth traffic. Here, identification of a low link utilization period is more difficult and the potential for energy savings is reduced. What is needed therefore is a mechanism that can produce energy savings during active idle signal transmissions.